I haven't purchased beer before, but I have ordered other alcohols before (wine, liquor, etc) and haven't had any issues. Shipping isn't really that cheap, though. I do recommend talking to your local stores first. Sometimes they can order them for you and you can just pick it up in store to skip the shipping costs. They might charge you an order fee, but some of them are just happy to order you anything they have access to because they can make a small profit off it regardless.
This is freaking me out. Why would anyone want to buy a beer online? How utterly puzzling. There are several convenience stores outside of our house so buying a beer online is just a tad bit too lazy. There should be a rule limiting the types of stuff you can sell online. Seriously. You can just go to a pub or buy a whole box of canned beers at the grocery store.
The only time I've ever bought beer online was when I had a house party and had 48 cans delivered by the local supermarket. I don't have a car so there was no way I could have carried them home. Other than that, I've never seen any deals on beer delivery. There's a few wine clubs here which offer case discounts but that's about it.
I have ordered online a few times, but you have to choose your company carefully. My favorite site to order from is Amazon, which is for a few reasons. I am a huge fan of whiskey but have quite expensive tastes. Amazon offer two of the whiskeys I love the most and usually have them at a good price. The last time I ordered, it only took two days to be delivered and was packed brilliantly with bubble wrap and foam for extra protection. The shipping was free with my order too, unlike some of the companies that will charge you an arm and a leg for the delivery! Have a look on Amazon because they tend to beat most online companies for price!